How often does rap move you to tears? The rhythm-propelled pop form hasn't traditionally concerned itself with the more introspective matters one would usually associate with emotional sensitivity - to say nothing of musical theatre. But when it's spoken from the heart, even it can be as devastating and elevating as a soaring ballad or a sweeping aria.

If you're incredulous - and, given Broadway's rap-friendly but stickily sentimental new Tony-winning Best Musical In the Heights, who wouldn't be? - the show that just opened at the Zipper Factory Theater might change your beat. It's called BASH'd: A Gay Rap Opera, and is every bit as unsettling and incongruous as its title promises. It's also edgier, sharper, and more legitimately moving than any other show in town.

In the 10 months since Canadian hit BASH'd first appeared in New York at the Fringe Festival, in the wake of Spring Awakening's great success at the Tonys, Broadway and Off-Broadway alike have seen no shortage of new musicals shedding off old forms and setting off in more modern directions. Even so, this show written by and starring Chris Craddock and Nathan Cuckow stands alone as an exemplar of this current genre: smarter, more soulful, and more necessary.

That's because Craddock and Cuckow haven't just co-opted the form for purposes of gimmickry. They, along with their composer Aaron Macri, use the violent music of the streets to examine and condemn the hate that dare not speak its name - as well as the reciprocal evil such hatred can inspire in even the purest of souls. In BASH'd, those souls manifest themselves in two ways: as the young Canadian men Jack and Dillon, who meet, marry, and then have their happiness ripped apart by intolerance; and the rappers who are presenting and performing their mosh-pit morality tale, T-Bag (Craddock) and Feminem (Cuckow). The two may not agree on certain details or political considerations, but they're uncommonly invested in seeing Jack and Dillon make it, despite all the forces - family, government, strangers - who might prefer they didn't.

So don't expect much in the way of propriety from these super-cool hip-hopsters (who have been clad in ridiculous, yet wildly appropriate pink-and-white getups by Chase Tyler). "All you real faggots pump your wrists in the air," the men shout, "Don't be straight, give a wave like you just don't care." Yes, for them it's war - they're on the frontlines, and they know which weapons to use. "We don't like faggot when it's said by them / But when we say it it's like a word that starts with N."

All this, for the record, happens within the first five minutes - from the get-go, there's no question what you'll be getting from T-Bag and Feminem. It may be less immediately clear how all of the disparate pieces fit together. T-Bag and Feminem's concert atmosphere - which is adroitly ornamented by Bradley Clements's lighting and Kris Pierce's sound design - is often distinctly at odds with the relatively quiet central love story they enact. Conventions are embraced (Dillon's father is a conservative nut willing to instantly disown his son, though he's not completely incapable of coming around) or exploded (Jack has two fabulously flamboyant fathers) in very obvious ways, and even when Jack and DIllon's saga sours, it takes few surprising turns.

But the lyrics, despite hardly comporting with traditional musical-theatre rhyming (blind devotees of the perfect rhyme, stay far away), smooth over any rough spots with their sheer force and variety. Weaving from ferocious to comic to regretful with an astonishing fluidity, they capture the roller-coaster sensations of first love without a trace of cheesiness and first hate without undue acridity. Every moment, whether oppressive, obsessive, or combative rings with the stark truthfulness that characterizes the best rap and the best musicals alike.

Director Ron Jenkins harnesses Craddock and Cuckow's natural perpetual-motion proclivities into potent performances that match the writing at every turn. They make the first evening Jack and Dillon spend together a lovely recreation of blossoming feelings, Cuckow's all-consuming uncertainty the ideal counterpart for Craddock's tough-guy façade crumbling within full view. They're hilarious detailing the denizens of gay bars, and riveting when they turn on each other in the wake of the homophobic attack around which the last third of the perfectly paced, hourlong evening revolves.

It's also that incident that sparks this show to individual greatness. As entertaining as Craddock and Cuckow make the show, and as invigorating as its craft proves at every step along the way, it's only once the full tale has unfolded that a meaningful diversion becomes goosebump-inducing, tearjerking theatre. Seeing how romance can become rage and rage can become retribution is a sobering reminder of something we'd all probably prefer to forget, but that the show reminds us should never be ignored: Hate is contagious, and no one is immune. If BASH'd isn't a permanent cure, it's at least the next best thing.